After a 12% decline in keratoplasties in the USA between 2004 and 2006, a 37% increase has occurred in the last 2 years with nearly 60,000 cases performed in 2009. As with the Cornea Donor Study (CDS) 10 years ago, a public health issue is again raised regarding the future adequacy of the donor pool. This increase has been driven by the emergence of endothelial keratoplasty (EK) which has become the procedure of choice for endothelial failure conditions, tripling in cases between 2006-09, and 30% of the keratoplasties last year. With a higher primary donor failure than penetrating keratoplasty (PKP), an aging population with more pathology, changes in the cornea evaluation process with increased regulations and more testing requirements for emerging infections and the threat to the donor pool from these infections, additional means to expand the donor pool besides the use of older donor tissue are needed. One major opportunity is to extend the use of donor tissue to the FDA approved preservation time of 14 days for intermediate storage media at 4?C (Optisol GS and Life 4 C). Corneas preserved beyond 7 days are rarely used for PKP or EK in the United States, but are regularly exported for successful use internationally. While existing data do not support this bias, an evidence based study is needed to change this practice paftern. The primary objectives of our study are to determine whether recipient corneal stroma clarity and endothelial cell loss, the two best measures for EK success, are comparable 3 years postoperatively for donor corneas preserved for 7 days or less compared to those preserved for between 8 and 14 days utilizing a randomized, prospective, masked clinical trial design. Two separate grant applications have been submitted. The Data Management and Analysis Center at the Jaeb Center for Health Research, which directed the CDS, will oversee all aspects of eye bank participation in the study, multi-functional website development, statistical plan, data management and analysis, and coordination of the DSMC. The Coordinating Center at CWRU and the UH Eye Institute, directed by the PI and Director, will provide scientific direction and coordination of the clinical sites, as well as oversee the Cornea Image Analysis Reading Center. RELEVANCE (See instmctions): If longer preservation time up to the FDA limit of 14 days can be shown to not adversely impact graft success and endothelial cell loss at 3 years, more donor tissue will be available to be efficiently distributed within the United States for all keratoplasty procedures, there will be more flexibility in time for extended testing for a suspected emerging infection, and less tissue will be exported due to exceeding a perceived limit of seven davs in storage